Independent report

Processed foods and health: SACN's rapid evidence update summary

Published 2 April 2025

Introduction

In 2023, the Scientific Advisory Committee on Nutrition (SACN) published a position statement on processed foods and health. The statement:

• evaluated existing classifications of processed foods, including ultra-processed foods (UPF) and the NOVA classification (a food classification that categorises foods according to the extent and purpose of food processing, rather than in terms of nutrients)
• evaluated the suitability and methods to apply food processing definitions as a dietary exposure
• considered the availability and quality of evidence associating different forms or levels of food processing with health outcomes

Of the 8 processed food classifications identified, NOVA (including its ‘ultra-processed food’ (UPF) category) was the only one that met  SACN’s initial screening criteria as being potentially suitable for use in the UK. However, SACN identified some concerns around its practical application. SACN also noted that the research literature investigating the health impacts of processed foods was dominated by NOVA.

Overall, SACN concluded that the association between higher consumption of (ultra) processed foods and adverse health outcomes is concerning. However, limitations in the available evidence meant that it was unclear whether these foods are inherently unhealthy due to processing or because a large majority of them are high in energy (calories), saturated fat, salt and/or free sugars.

SACN made a range of research recommendations.

Given their concerns, SACN committed to considering the issue again.

This rapid update considers new evidence on the topic and whether any further assessment is necessary.

Background

Recent publications

Since the SACN position statement on processed foods and health was published in July 2023, there have been a number of relevant publications.

Also in July 2023, SACN published its report Feeding young children aged 1 to 5 years. The report highlighted that commercial baby foods are one of the main contributors to energy and free sugars intake for children in this age group who ate these products, and that eating sweet and savoury snack foods increased with age. SACN made several recommendations about processed foods and drinks.

In March 2024, the Government Office for Science published summaries of 2 expert roundtables on this topic in a science advice note on ultra-processed foods. The summaries recommend that, given the increasing number of studies in this field, future reports should only include higher quality evidence. The summaries also note the potential for further developing UPF subcategories based on nutritional composition, as well as those based on processing. Evidence gaps identified by SACN were also  considered.

Following SACN’s research recommendations, the National Institute for Health and Care Research published research calls on UPF and on early years nutrition.

All foods containing non-sugar sweeteners (NSS) are classified as UPF under the NOVA definition. In May 2023 the World Health Organization (WHO) guideline Use of non-sugar sweeteners stated that “non-sugar sweeteners (NSS) not be used as a means of achieving weight control or reducing the risk of noncommunicable diseases”.

The WHO guideline highlights that there continues to be uncertainties in the evidence base on sweeteners and the role they may play in supporting weight management. SACN has reviewed the WHO guideline and associated evidence, and has made a number of recommendations in its 2025 position statement on non-sugar sweeteners.

International recommendations

SACN’s 2023 position statement on processed foods and health reported that several countries refer to food processing in their national dietary guidelines, including Belgium, Brazil, Brunei Darussalam, Ecuador, Israel, Kenya, Maldives, Malta, New Zealand, Peru and Uruguay.

Since then, the following relevant guidelines have been published.

The Nordic Nutrition Recommendations 2023 recommend “minimal intake of … processed foods containing high amounts of added fats, salt and sugar”. However, it notes that “the categorization of foods as UPF does not add to the already existing food classifications and recommendations”. The report notes that the approach taken is in line with guidelines from the USA, Canada and most European countries.

The Scientific Report of the 2025 US Dietary Guidelines Advisory Committee concluded that while there were associations between dietary patterns high in UPF and adverse health outcomes, the certainty of the evidence was “limited”. The report notes that the “body of evidence was difficult to assess, largely because of the lack of clear definition of ultra-processed foods”.

Methods

Assessment of the evidence for this rapid update is consistent with the SACN framework for the evaluation of evidence (for more information see the SACN webpage).

Given the dominance of NOVA in the literature, only studies using NOVA were included.

In line with discussions at the Government Office for Science expert round tables, this evidence update focuses on higher quality evidence.

Research databases were searched to identify:

• umbrella reviews (URs) - all evidence types
• systematic reviews (SRs) with or without meta-analyses (MAs) that included separate analysis of prospective cohort studies (PCS) and/or randomised controlled trial (RCT) data
• PCS that include subgroup analysis or substitution analysis
• RCTs

Papers applying NOVA to the National Diet and Nutrition Survey were identified through Google Scholar alerts.

The trial registry website ClinicalTrials.gov was also searched for relevant registered trials.

Results

National Diet and Nutrition Survey evidence

SACN’s 2023 position statement on processed foods and health identified a range of limitations in applying NOVA to the UK National Diet and Nutrition Survey (NDNS). It reported that estimates of UPF consumption in the NDNS data ranged from 51% energy in adults to 68% energy in children.

For this update, one study applied NOVA to NDNS intake data. The study reported partial overlap between the UPF classification and food and drinks high in saturated fat, salt or sugars. UPFs tended to have an “unhealthier” nutritional profile than “minimally processed” foods. The authors noted that not all UPFs were considered “unhealthy” by their definitions.

Umbrella reviews and systematic reviews

The search identified:

• 5 URs
• 8 SRs of PCS only
• 11 SRs of observational studies with a separate analysis by PCS

The majority of URs and SRs reported that increased consumption of UPF was associated with increased risk of adverse health outcomes such as:

• obesity
• type 2 diabetes
• cardiovascular disease
• cancer
• mental health conditions

Prospective cohort studies subgroup analysis

Ten PCS were identified that carried out a subgroup analysis by food type.

The range of food groups considered made it difficult to compare the findings from the different studies. However, analyses suggest that UPF categories, including meat and animal products and sweetened drinks, tend to be associated with an increased risk of adverse health outcomes. In contrast, UPF categories including vegetarian alternatives were not associated with adverse health outcomes. Mixed results were found for UPF categories including:

• bread and cereals
• savoury snacks
• dairy products
• sweets and desserts
• sauces and spreads
• fats
• ready to eat foods
• alcoholic drinks

Randomised controlled trials

One small RCT including 9 people was identified that found participants gained more weight (1.1kg) on a UPF diet compared to a non-UPF diet. A check of a trial registry indicated that a number of registered trials were underway, including studies considering food texture and eating rate.

Limitations

The quality of the identified evidence was not formally assessed.

The limitations identified in SACN’s 2023 position statement on processed foods and health remain. In particular, studies appear to inconsistently account for important factors such as:

• socioeconomic status
• body mass index
• energy
• nutritional intake

All of these may be related to the health outcomes considered.

Authors of PCS with subgroup analyses detailed common limitations of their studies, including issues relating to:

• data collection methods
• the age of dietary data and how relevant it is given the wide variety of UPF available today
• difficulties in applying the NOVA classification system
• study length and difficulty identifying the contribution of UPF to long term health outcomes
• confounding (factors that are related to both UPF consumption and the health outcomes being considered), selection bias (whether the study sample is representative of the group of people being studied), and generalisability of the findings (whether the findings can be applied to the general UK population)

Discussion

URs and SRs of PCS published since March 2023 reported that increased consumption of UPF was associated with increased risks of adverse health outcomes. This is consistent with findings from SACN’s 2023 position statement on processed foods and health.

Additional analyses by subcategories of UPF indicate that not all UPFs may affect health in the same way. The categories of UPF consistently associated with adverse health outcomes were those including meat and animal products and sweetened drinks.

The available evidence remains almost exclusively observational, with only one small RCT identified. There also continues to be methodological issues with the available evidence. For example, studies appear to adjust for important factors inconsistently, particularly for measures of socioeconomic status and body mass index. Even after adjustments have been made, it is likely that some confounding will remain.

This is a very active research area. There are a number of ongoing registered trials. In addition, better quality observational data and SRs are also likely to be published, which may address some of the issues identified in the current evidence base.

In previous reports SACN has already made a number of recommendations about processed foods and drinks:

SACN’s Iron and health report recommended that adults with relatively high intakes of red and processed meat (over 90g per day) should consider reducing their intakes to the population average for adults (about 70g per day). This is due to an association between red and processed meat and bowel cancer.

SACN’s Carbohydrates and health report recommended that:

• sugar-sweetened drinks should be minimised given observed associations with risk of weight gain in children and dental caries and type 2 diabetes
• intakes of fibre should increase due to wide ranging health benefits, including reducing the risk of bowel cancer - the recommendation means eating more wholegrain starchy foods, vegetables and fruit

SACN’s 2023 report Feeding young children aged 1 to 5 years recommended that:

• foods (including snacks) that are energy dense and high in saturated fat, salt or free sugars should be limited
• dairy products including yogurts should ideally be unsweetened
• sugar-sweetened beverages should not be given to young children
• follow-on formula and commercially manufactured foods and drinks marketed specifically for infants and young children are not necessary to meet nutritional requirements for this age group

In March 2025, SACN published a position statement on the WHO guideline on non-sugar sweeteners.

Higher consumption of UPF is likely to reflect (at least in part) a less healthy dietary pattern. SACN has already concluded in previous risk assessments that consumption of excess energy (calories), saturated fat, salt, free sugars and processed meat is linked to poor health outcomes. And that higher consumption of fruit and vegetables, wholegrain foods and fibre reduces health risks.

Existing UK dietary advice, based on SACN recommendations, is largely consistent with international recommendations. Some countries recommend eating fewer or avoiding UPF or processed foods, or recommend eating minimally processed foods.

Conclusions

SACN has found consistent associations between higher consumption of UPF and adverse health outcomes. SACN continues to find the observed associations between higher consumption of (ultra) processed foods and adverse health outcomes concerning.

There continues to be significant limitations in the evidence base. It remains unclear to what extent observed associations between UPFs and adverse health outcomes are explained by established relationships between nutritional factors and health outcomes on which SACN has undertaken risk assessments.

There are still concerns and difficulties around the commonly used NOVA classification system. However, further subgroup analysis of foods classified as UPF suggests there may be some potential to develop subcategories within the existing NOVA classification based on nutritional composition, in addition to processing.

SACN notes that subgroup analyses to date indicate increased risk of poor health outcomes for a number of food categories including meat and products and sweetened drinks. SACN has already made recommendations about these foods (see above). The reasons for diverse findings for other subgroups remain unclear.

The UK’s national food model the Eatwell Guide, which is based on SACN’s recommendations, already indicates that many foods classified as ultra processed such as crisps, biscuits, cakes, confectionery and ice cream are not part of a healthy, balanced diet. It also emphasises a diet based on fruit, vegetables and wholegrain or higher fibre starchy carbohydrates, with less red and processed meat and less foods high in saturated fat, salt and free sugars.

The dietary data collection tool in the NDNS rolling programme is under continuous review as part of the NDNS contract, so there is an opportunity to make changes to data capture to achieve better estimates of UPF intake. However, this would require data on additives in foods.

SACN will keep the topic under annual review and consider it again in 2026.

Recommendations

SACN has made the following recommendations in the context of existing UK government dietary recommendations and these should be read alongside its 2023 position statement.

On balance, most people are likely to benefit from reducing their consumption of processed foods high in energy, saturated fat, salt and free sugars, and low in fibre. This is consistent with previous SACN recommendations. It is based on the nutrient content of many UPFs and concerns raised about health.

SACN reiterates its existing advice on processed foods (see above), particularly on minimising intake of sugar-sweetened beverages and avoiding high intakes of red and processed meat.

SACN reiterates its recommendations on NSS. See the 2025 position statement on NSS for a full list of these.

SACN recommends that the government:

• considers strategies and actions to implement SACN’s existing recommendations on processed foods
• considers whether including messaging on processing improves dietary intakes - particularly for eating fewer processed foods that are high in saturated fat, salt and sugar - without unintended adverse consequences
• compels industry to make its processing data publicly available to enable monitoring and further research on associations with health outcomes - publicly available data is required on the amounts of individual additives such as emulsifiers and NSS within food products and the specific processing methods used
• monitors the consumption of individual additives such as emulsifiers and NSS in the UK diet, particularly among high consuming and vulnerable groups
• continues to review opportunities to monitor consumption of processed foods using the NDNS

Research recommendations

SACN is aware of considerable ongoing research on this topic, both nationally and internationally. SACN encourages research funders to focus attention on the priority areas highlighted in its 2023 position statement, chapter 5 of this rapid review and the expert roundtables outlined above.